diff options
Diffstat (limited to 'drivers/rtc/rtc-lpc32xx.c')
| -rw-r--r-- | drivers/rtc/rtc-lpc32xx.c | 360 |
1 files changed, 360 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-lpc32xx.c b/drivers/rtc/rtc-lpc32xx.c new file mode 100644 index 000000000..15d8abda8 --- /dev/null +++ b/drivers/rtc/rtc-lpc32xx.c @@ -0,0 +1,360 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2010 NXP Semiconductors + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/spinlock.h> +#include <linux/rtc.h> +#include <linux/slab.h> +#include <linux/io.h> +#include <linux/of.h> + +/* + * Clock and Power control register offsets + */ +#define LPC32XX_RTC_UCOUNT 0x00 +#define LPC32XX_RTC_DCOUNT 0x04 +#define LPC32XX_RTC_MATCH0 0x08 +#define LPC32XX_RTC_MATCH1 0x0C +#define LPC32XX_RTC_CTRL 0x10 +#define LPC32XX_RTC_INTSTAT 0x14 +#define LPC32XX_RTC_KEY 0x18 +#define LPC32XX_RTC_SRAM 0x80 + +#define LPC32XX_RTC_CTRL_MATCH0 (1 << 0) +#define LPC32XX_RTC_CTRL_MATCH1 (1 << 1) +#define LPC32XX_RTC_CTRL_ONSW_MATCH0 (1 << 2) +#define LPC32XX_RTC_CTRL_ONSW_MATCH1 (1 << 3) +#define LPC32XX_RTC_CTRL_SW_RESET (1 << 4) +#define LPC32XX_RTC_CTRL_CNTR_DIS (1 << 6) +#define LPC32XX_RTC_CTRL_ONSW_FORCE_HI (1 << 7) + +#define LPC32XX_RTC_INTSTAT_MATCH0 (1 << 0) +#define LPC32XX_RTC_INTSTAT_MATCH1 (1 << 1) +#define LPC32XX_RTC_INTSTAT_ONSW (1 << 2) + +#define LPC32XX_RTC_KEY_ONSW_LOADVAL 0xB5C13F27 + +#define rtc_readl(dev, reg) \ + __raw_readl((dev)->rtc_base + (reg)) +#define rtc_writel(dev, reg, val) \ + __raw_writel((val), (dev)->rtc_base + (reg)) + +struct lpc32xx_rtc { + void __iomem *rtc_base; + int irq; + unsigned char alarm_enabled; + struct rtc_device *rtc; + spinlock_t lock; +}; + +static int lpc32xx_rtc_read_time(struct device *dev, struct rtc_time *time) +{ + unsigned long elapsed_sec; + struct lpc32xx_rtc *rtc = dev_get_drvdata(dev); + + elapsed_sec = rtc_readl(rtc, LPC32XX_RTC_UCOUNT); + rtc_time64_to_tm(elapsed_sec, time); + + return 0; +} + +static int lpc32xx_rtc_set_time(struct device *dev, struct rtc_time *time) +{ + struct lpc32xx_rtc *rtc = dev_get_drvdata(dev); + u32 secs = rtc_tm_to_time64(time); + u32 tmp; + + spin_lock_irq(&rtc->lock); + + /* RTC must be disabled during count update */ + tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL); + rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp | LPC32XX_RTC_CTRL_CNTR_DIS); + rtc_writel(rtc, LPC32XX_RTC_UCOUNT, secs); + rtc_writel(rtc, LPC32XX_RTC_DCOUNT, 0xFFFFFFFF - secs); + rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp &= ~LPC32XX_RTC_CTRL_CNTR_DIS); + + spin_unlock_irq(&rtc->lock); + + return 0; +} + +static int lpc32xx_rtc_read_alarm(struct device *dev, + struct rtc_wkalrm *wkalrm) +{ + struct lpc32xx_rtc *rtc = dev_get_drvdata(dev); + + rtc_time64_to_tm(rtc_readl(rtc, LPC32XX_RTC_MATCH0), &wkalrm->time); + wkalrm->enabled = rtc->alarm_enabled; + wkalrm->pending = !!(rtc_readl(rtc, LPC32XX_RTC_INTSTAT) & + LPC32XX_RTC_INTSTAT_MATCH0); + + return rtc_valid_tm(&wkalrm->time); +} + +static int lpc32xx_rtc_set_alarm(struct device *dev, + struct rtc_wkalrm *wkalrm) +{ + struct lpc32xx_rtc *rtc = dev_get_drvdata(dev); + unsigned long alarmsecs; + u32 tmp; + + alarmsecs = rtc_tm_to_time64(&wkalrm->time); + + spin_lock_irq(&rtc->lock); + + /* Disable alarm during update */ + tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL); + rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp & ~LPC32XX_RTC_CTRL_MATCH0); + + rtc_writel(rtc, LPC32XX_RTC_MATCH0, alarmsecs); + + rtc->alarm_enabled = wkalrm->enabled; + if (wkalrm->enabled) { + rtc_writel(rtc, LPC32XX_RTC_INTSTAT, + LPC32XX_RTC_INTSTAT_MATCH0); + rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp | + LPC32XX_RTC_CTRL_MATCH0); + } + + spin_unlock_irq(&rtc->lock); + + return 0; +} + +static int lpc32xx_rtc_alarm_irq_enable(struct device *dev, + unsigned int enabled) +{ + struct lpc32xx_rtc *rtc = dev_get_drvdata(dev); + u32 tmp; + + spin_lock_irq(&rtc->lock); + tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL); + + if (enabled) { + rtc->alarm_enabled = 1; + tmp |= LPC32XX_RTC_CTRL_MATCH0; + } else { + rtc->alarm_enabled = 0; + tmp &= ~LPC32XX_RTC_CTRL_MATCH0; + } + + rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp); + spin_unlock_irq(&rtc->lock); + + return 0; +} + +static irqreturn_t lpc32xx_rtc_alarm_interrupt(int irq, void *dev) +{ + struct lpc32xx_rtc *rtc = dev; + + spin_lock(&rtc->lock); + + /* Disable alarm interrupt */ + rtc_writel(rtc, LPC32XX_RTC_CTRL, + rtc_readl(rtc, LPC32XX_RTC_CTRL) & + ~LPC32XX_RTC_CTRL_MATCH0); + rtc->alarm_enabled = 0; + + /* + * Write a large value to the match value so the RTC won't + * keep firing the match status + */ + rtc_writel(rtc, LPC32XX_RTC_MATCH0, 0xFFFFFFFF); + rtc_writel(rtc, LPC32XX_RTC_INTSTAT, LPC32XX_RTC_INTSTAT_MATCH0); + + spin_unlock(&rtc->lock); + + rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF); + + return IRQ_HANDLED; +} + +static const struct rtc_class_ops lpc32xx_rtc_ops = { + .read_time = lpc32xx_rtc_read_time, + .set_time = lpc32xx_rtc_set_time, + .read_alarm = lpc32xx_rtc_read_alarm, + .set_alarm = lpc32xx_rtc_set_alarm, + .alarm_irq_enable = lpc32xx_rtc_alarm_irq_enable, +}; + +static int lpc32xx_rtc_probe(struct platform_device *pdev) +{ + struct lpc32xx_rtc *rtc; + int err; + u32 tmp; + + rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); + if (unlikely(!rtc)) + return -ENOMEM; + + rtc->rtc_base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(rtc->rtc_base)) + return PTR_ERR(rtc->rtc_base); + + spin_lock_init(&rtc->lock); + + /* + * The RTC is on a separate power domain and can keep it's state + * across a chip power cycle. If the RTC has never been previously + * setup, then set it up now for the first time. + */ + tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL); + if (rtc_readl(rtc, LPC32XX_RTC_KEY) != LPC32XX_RTC_KEY_ONSW_LOADVAL) { + tmp &= ~(LPC32XX_RTC_CTRL_SW_RESET | + LPC32XX_RTC_CTRL_CNTR_DIS | + LPC32XX_RTC_CTRL_MATCH0 | + LPC32XX_RTC_CTRL_MATCH1 | + LPC32XX_RTC_CTRL_ONSW_MATCH0 | + LPC32XX_RTC_CTRL_ONSW_MATCH1 | + LPC32XX_RTC_CTRL_ONSW_FORCE_HI); + rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp); + + /* Clear latched interrupt states */ + rtc_writel(rtc, LPC32XX_RTC_MATCH0, 0xFFFFFFFF); + rtc_writel(rtc, LPC32XX_RTC_INTSTAT, + LPC32XX_RTC_INTSTAT_MATCH0 | + LPC32XX_RTC_INTSTAT_MATCH1 | + LPC32XX_RTC_INTSTAT_ONSW); + + /* Write key value to RTC so it won't reload on reset */ + rtc_writel(rtc, LPC32XX_RTC_KEY, + LPC32XX_RTC_KEY_ONSW_LOADVAL); + } else { + rtc_writel(rtc, LPC32XX_RTC_CTRL, + tmp & ~LPC32XX_RTC_CTRL_MATCH0); + } + + platform_set_drvdata(pdev, rtc); + + rtc->rtc = devm_rtc_allocate_device(&pdev->dev); + if (IS_ERR(rtc->rtc)) + return PTR_ERR(rtc->rtc); + + rtc->rtc->ops = &lpc32xx_rtc_ops; + rtc->rtc->range_max = U32_MAX; + + err = rtc_register_device(rtc->rtc); + if (err) + return err; + + /* + * IRQ is enabled after device registration in case alarm IRQ + * is pending upon suspend exit. + */ + rtc->irq = platform_get_irq(pdev, 0); + if (rtc->irq < 0) { + dev_warn(&pdev->dev, "Can't get interrupt resource\n"); + } else { + if (devm_request_irq(&pdev->dev, rtc->irq, + lpc32xx_rtc_alarm_interrupt, + 0, pdev->name, rtc) < 0) { + dev_warn(&pdev->dev, "Can't request interrupt.\n"); + rtc->irq = -1; + } else { + device_init_wakeup(&pdev->dev, 1); + } + } + + return 0; +} + +#ifdef CONFIG_PM +static int lpc32xx_rtc_suspend(struct device *dev) +{ + struct lpc32xx_rtc *rtc = dev_get_drvdata(dev); + + if (rtc->irq >= 0) { + if (device_may_wakeup(dev)) + enable_irq_wake(rtc->irq); + else + disable_irq_wake(rtc->irq); + } + + return 0; +} + +static int lpc32xx_rtc_resume(struct device *dev) +{ + struct lpc32xx_rtc *rtc = dev_get_drvdata(dev); + + if (rtc->irq >= 0 && device_may_wakeup(dev)) + disable_irq_wake(rtc->irq); + + return 0; +} + +/* Unconditionally disable the alarm */ +static int lpc32xx_rtc_freeze(struct device *dev) +{ + struct lpc32xx_rtc *rtc = dev_get_drvdata(dev); + + spin_lock_irq(&rtc->lock); + + rtc_writel(rtc, LPC32XX_RTC_CTRL, + rtc_readl(rtc, LPC32XX_RTC_CTRL) & + ~LPC32XX_RTC_CTRL_MATCH0); + + spin_unlock_irq(&rtc->lock); + + return 0; +} + +static int lpc32xx_rtc_thaw(struct device *dev) +{ + struct lpc32xx_rtc *rtc = dev_get_drvdata(dev); + + if (rtc->alarm_enabled) { + spin_lock_irq(&rtc->lock); + + rtc_writel(rtc, LPC32XX_RTC_CTRL, + rtc_readl(rtc, LPC32XX_RTC_CTRL) | + LPC32XX_RTC_CTRL_MATCH0); + + spin_unlock_irq(&rtc->lock); + } + + return 0; +} + +static const struct dev_pm_ops lpc32xx_rtc_pm_ops = { + .suspend = lpc32xx_rtc_suspend, + .resume = lpc32xx_rtc_resume, + .freeze = lpc32xx_rtc_freeze, + .thaw = lpc32xx_rtc_thaw, + .restore = lpc32xx_rtc_resume +}; + +#define LPC32XX_RTC_PM_OPS (&lpc32xx_rtc_pm_ops) +#else +#define LPC32XX_RTC_PM_OPS NULL +#endif + +#ifdef CONFIG_OF +static const struct of_device_id lpc32xx_rtc_match[] = { + { .compatible = "nxp,lpc3220-rtc" }, + { } +}; +MODULE_DEVICE_TABLE(of, lpc32xx_rtc_match); +#endif + +static struct platform_driver lpc32xx_rtc_driver = { + .probe = lpc32xx_rtc_probe, + .driver = { + .name = "rtc-lpc32xx", + .pm = LPC32XX_RTC_PM_OPS, + .of_match_table = of_match_ptr(lpc32xx_rtc_match), + }, +}; + +module_platform_driver(lpc32xx_rtc_driver); + +MODULE_AUTHOR("Kevin Wells <wellsk40@gmail.com"); +MODULE_DESCRIPTION("RTC driver for the LPC32xx SoC"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:rtc-lpc32xx"); |